6.1
Medium
tinymce

CVE-2020-12648

CVE-2020-12648 is a medium-severity cross-site scripting (XSS) vulnerability in tinymce (npm), affecting versions < 4.9.11. It is fixed in 4.9.11, 5.4.1.

Key facts
CVSS score
6.1
Medium
Attack vector
Network
Issuing authority
GitHub Advisory Database
Affected package
tinymce
Fixed in
4.9.11, 5.4.1
Disclosed
2020

Summary

Impact A cross-site scripting (XSS) vulnerability was discovered in the core parser. The vulnerability allowed arbitrary JavaScript execution when inserting a specially crafted piece of content into the editor via the clipboard or APIs. This impacts all users who are using TinyMCE 4.9.10 or lower and TinyMCE 5.4.0 or lower. Patches This vulnerability has been patched in TinyMCE 4.9.11 and 5.4.1 by improved HTML parsing and sanitization logic. Workarounds The workarounds available are: upgrade to either TinyMCE 4.9.11 or TinyMCE 5.4.1 or enable the media plugin, which overrides the default parsing behaviour for iframes or add the following workaround to update the parsing schema rules for iframes: Example: Change the default schema for iframes Acknowledgements Tiny Technologies would like to thank George Steketee and Chris Davis at Bishop Fox for discovering this vulnerability. References https://www.tiny.cloud/docs/release-notes/release-notes54/#securityfixes For more information If you have any questions or comments about this advisory: Open an issue in the TinyMCE repo Email us at [email protected]

Impact

What is cross-site scripting (XSS)?

Untrusted input is rendered as active markup in a victim's browser, which can run script in their session. Typical impact: session or credential theft, and actions taken as the user.

Severity and exposure

CVE-2020-12648 has a CVSS score of 6.1 (Medium). The vector is network-reachable, no privileges required, and user interaction required. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment.

A fixed version is available (4.9.11, 5.4.1). Upgrading removes the vulnerable code path.

Affected versions

npm

  • tinymce (< 4.9.11)
  • tinymce (>= 5.0.0, < 5.4.1)

Security releases

  • tinymce → 4.9.11 (npm)
  • tinymce → 5.4.1 (npm)
Kodem intelligence

Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.

Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter instead of chasing every advisory.

Kodem's runtime-powered SCA identifies whether CVE-2020-12648 is reachable in your applications. Explore open-source security for your team.

See if CVE-2020-12648 is reachable in your applications. Get a demo

Remediation advice

Upgrade the following packages to resolve this vulnerability:

  • Upgrade tinymce to 4.9.11 or later
  • Upgrade tinymce to 5.4.1 or later

Kodem Kai can prioritize this vulnerability in your dependency tree and generate a fix recommendation.

Frequently asked questions about CVE-2020-12648

What is CVE-2020-12648?

CVE-2020-12648 is a medium-severity cross-site scripting (XSS) vulnerability in tinymce (npm), affecting versions < 4.9.11. It is fixed in 4.9.11, 5.4.1. Untrusted input is rendered as active markup in a victim's browser, which can run script in their session.

How severe is CVE-2020-12648?

CVE-2020-12648 has a CVSS score of 6.1 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.

Which versions of tinymce are affected by CVE-2020-12648?

tinymce (npm) versions < 4.9.11 is affected.

Is there a fix for CVE-2020-12648?

Yes. CVE-2020-12648 is fixed in 4.9.11, 5.4.1. Upgrade to this version or later.

Is CVE-2020-12648 exploitable, and should I be worried?

Whether CVE-2020-12648 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo

What actually determines whether CVE-2020-12648 is exploitable, and how bad it is?

Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.

How do I fix CVE-2020-12648?
  • Upgrade tinymce to 4.9.11 or later
  • Upgrade tinymce to 5.4.1 or later

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